linux-kernel - Re: [PATCH] cpupower: mperf monitor: fix output in MAX_FREQ

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Date:	Wed, 27 May 2015 15:24:56 +0200
From:	Thomas Renninger <trenn@...e.de>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:	"Herton R. Krzesinski" <herton@...hat.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] cpupower: mperf monitor: fix output in MAX_FREQ_SYSFS mode

Hi,

and sorry for the late answer, this had not highest prio...

On Wednesday, May 20, 2015 02:26:47 AM Rafael J. Wysocki wrote:
> On Monday, May 11, 2015 12:40:22 PM Herton R. Krzesinski wrote:
> > On Mon, May 11, 2015 at 11:35:35AM -0300, Herton R. Krzesinski wrote:
> > > There is clearly wrong output when mperf monitor runs in MAX_FREQ_SYSFS
> > > mode: average frequency shows in kHz unit (despite the intended output
> > > to be in MHz), and percentages for C state information are all wrong
> > > (including high/negative values shown).
> > > 
> > > The problem is that the max_frequency read on initialization isn't used
> > > where it should have been used on mperf_get_count_percent (to estimate
> > > the number of ticks in the given time period), and the value we read
> > > from sysfs is in kHz, so we must divide it to get the MHz value to use
> > > in current calculations.
> > > 
> > > While at it, also I fixed another small issues in the debug output of
> > > max_frequency value in mperf_get_count_freq.
> > > 
> > > Signed-off-by: Herton R. Krzesinski <herton@...hat.com>
> > > ---
> > > 
> > >  tools/power/cpupower/utils/idle_monitor/mperf_monitor.c | 5 +++--
> > >  1 file changed, 3 insertions(+), 2 deletions(-)
> > 
> > Actually please consider v2 patch below, just a minor change in the debug
> > output, which isn't a percentage...
> 
> Thomas, any comments?

I tried to find fitting HW without much success.
The MAX_FREQ_SYSFS is used only on rare HW and it may never got a proper test.

Patch looks sane. Even I cannot add a Tested-by:
you may add:

Acked-by: Thomas Renninger <trenn@...e.de>

and add it.

Thanks,

       Thomas
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